The present invention relates to a power switching device, especially one intended for interconnection modules for internal combustion engine vehicles or electric vehicles, using semiconductor switching members whose dissipated thermal power has to be optimally extracted.
Document FR 2 800 567 discloses a power switching device comprising semiconductor switching members having two sets of connections, said semiconductor devices being fixed by their base to a cooling plate made of copper or other conductor metal to which the first set of connections is connected, while the second set of connections of the semiconductor devices is connected to a control circuit and to power connectors. The switching members are, for example, of the MOSFET or Smart Power type; in the case of a MOSFET member, the first set of connections includes the drain and the second set of connections includes the gate and the source; in the case of a Smart Power member, the first set of connections includes the supply and the second set of connections includes the 1 to n inputs, the 1 to n outputs, the current sensor and ground. The switching members advantageously include a sole (the drain in the case of a MOSFET) that is directly affixed to the cooling plate by soldering or pressing. The cooling plate itself is affixed to a plastic support plate constituting part of a package and contributing to dissipating heat to the outside by radiation. The connections of the second set of connections of the switching members are connected by transverse pins to a routing circuit placed parallel to the cooling plate. These pins are formed by leads cut and folded from the copper plate serving for cooling and for equipotentialization of the first connections. The fact that the electrical distribution and the thermal cooling are carried out by one and the same copper plate imposes limitations on the possible ways of organizing the circuits and of making them compact.